Sending OpenAI Chat Completion Traces

This guide explains how to send OpenTelemetry-compatible traces for OpenAI chat completions to Langtrace using cURL. Here’s an example of how your traces will appear in the Langtrace UI after following this guide:

Prerequisites

Langtrace API Key
OpenAI API Key (for comparison with SDK usage)

Endpoint

POST http://localhost:3000/api/trace  # For local development
# or
POST https://api.langtrace.ai/api/trace  # For production

Headers

Content-Type: application/json
x-api-key: YOUR_LANGTRACE_API_KEY
User-Agent: opentelemetry-python

Trace Format

The trace must follow the OpenTelemetry format and include specific attributes for OpenAI chat completions. Note that attributes must use the OpenTelemetry value format with stringValue or intValue:

{
  "resourceSpans": [{
    "resource": {
      "attributes": [{
        "key": "service.name",
        "value": { "stringValue": "your-service-name" }
      }]
    },
    "scopeSpans": [{
      "scope": {
        "name": "openai",
        "version": "1.0.0"
      },
      "spans": [{
        "name": "OpenAI ChatCompletion",
        "kind": 2,  // SpanKind.CLIENT
        "startTimeUnixNano": "1234567890000000000",
        "endTimeUnixNano": "1234567891000000000",
        "traceId": "a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6",
        "spanId": "a1b2c3d4e5f6g7h8",
        "attributes": [{
          "key": "llm.vendor",
          "value": { "stringValue": "openai" }
        }, {
          "key": "llm.request.model",
          "value": { "stringValue": "gpt-3.5-turbo" }
        }, {
          "key": "llm.request.messages",
          "value": { "stringValue": "[{\"role\": \"user\", \"content\": \"Hello\"}]" }
        }, {
          "key": "llm.path",
          "value": { "stringValue": "/v1/chat/completions" }
        }, {
          "key": "llm.request.temperature",
          "value": { "intValue": 0.7 }
        }, {
          "key": "llm.request.max_tokens",
          "value": { "intValue": 150 }
        }, {
          "key": "llm.usage.prompt_tokens",
          "value": { "intValue": 10 }
        }, {
          "key": "llm.usage.completion_tokens",
          "value": { "intValue": 15 }
        }, {
          "key": "llm.usage.total_tokens",
          "value": { "intValue": 25 }
        }]
      }]
    }]
  }]
}

Example cURL Command

curl -X POST "http://localhost:3000/api/trace" \
  -H "Content-Type: application/json" \
  -H "x-api-key: ${LANGTRACE_API_KEY}" \
  -H "User-Agent: opentelemetry-python" \
  -d '{
    "resourceSpans": [{
      "resource": {
        "attributes": [{
          "key": "service.name",
          "value": { "stringValue": "openai-test" }
        }]
      },
      "scopeSpans": [{
        "scope": {
          "name": "openai",
          "version": "1.0.0"
        },
        "spans": [{
          "name": "OpenAI ChatCompletion",
          "kind": 2,
          "startTimeUnixNano": "'$(date +%s%N)'",
          "endTimeUnixNano": "'$(date +%s%N)'",
          "traceId": "'$(openssl rand -hex 16)'",
          "spanId": "'$(openssl rand -hex 8)'",
          "attributes": [{
            "key": "llm.vendor",
            "value": { "stringValue": "openai" }
          }, {
            "key": "llm.request.model",
            "value": { "stringValue": "gpt-3.5-turbo" }
          }, {
            "key": "llm.request.messages",
            "value": { "stringValue": "[{\"role\": \"user\", \"content\": \"Hello\"}]" }
          }, {
            "key": "llm.path",
            "value": { "stringValue": "/v1/chat/completions" }
          }, {
            "key": "llm.request.temperature",
            "value": { "intValue": 0.7 }
          }, {
            "key": "llm.request.max_tokens",
            "value": { "intValue": 150 }
          }, {
            "key": "llm.usage.prompt_tokens",
            "value": { "intValue": 10 }
          }, {
            "key": "llm.usage.completion_tokens",
            "value": { "intValue": 15 }
          }, {
            "key": "llm.usage.total_tokens",
            "value": { "intValue": 25 }
          }]
        }]
      }]
    }]
  }'

Required Attributes

Attribute	Description	Required
llm.vendor	Service provider (“openai”)	Yes
llm.request.model	Model name (e.g., “gpt-3.5-turbo”)	Yes
llm.request.messages	JSON string of messages array	Yes
llm.path	API endpoint path	Yes
llm.request.temperature	Temperature setting	No
llm.request.max_tokens	Maximum tokens	No
llm.usage.*	Token usage statistics	No

Function Calling Example

When using OpenAI function calling, include the tools in the attributes with proper value formatting:

curl -X POST "http://localhost:3000/api/trace" \
  -H "Content-Type: application/json" \
  -H "x-api-key: ${LANGTRACE_API_KEY}" \
  -H "User-Agent: opentelemetry-python" \
  -d '{
    "resourceSpans": [{
      "resource": {
        "attributes": [{
          "key": "service.name",
          "value": { "stringValue": "openai-test" }
        }]
      },
      "scopeSpans": [{
        "scope": {
          "name": "openai",
          "version": "1.0.0"
        },
        "spans": [{
          "name": "OpenAI ChatCompletion",
          "kind": 2,
          "startTimeUnixNano": "'$(date +%s%N)'",
          "endTimeUnixNano": "'$(date +%s%N)'",
          "traceId": "'$(openssl rand -hex 16)'",
          "spanId": "'$(openssl rand -hex 8)'",
          "attributes": [{
            "key": "llm.vendor",
            "value": { "stringValue": "openai" }
          }, {
            "key": "llm.request.model",
            "value": { "stringValue": "gpt-3.5-turbo" }
          }, {
            "key": "llm.request.messages",
            "value": { "stringValue": "[{\"role\": \"user\", \"content\": \"What's the weather?\"}]" }
          }, {
            "key": "llm.path",
            "value": { "stringValue": "/v1/chat/completions" }
          }, {
            "key": "llm.tools",
            "value": { "stringValue": "[{\"type\": \"function\", \"function\": {\"name\": \"get_weather\", \"arguments\": \"{\\\"location\\\": \\\"London\\\"}\"}}]" }
          }]
        }]
      }]
    }]
  }'

Response Format

Success Response

{
  "message": "Traces added successfully"
}

Error Response

{
  "name": "Error name",
  "message": "Error message",
  "stack": "Error stack trace",
  "fullError": "Detailed error information"
}

Comparison with SDK Usage

For comparison, here’s how the same trace would be generated using the Python SDK:

from openai import OpenAI
from langtrace_python_sdk import langtrace

# Initialize clients
client = OpenAI()
langtrace.init(api_key="YOUR_LANGTRACE_API_KEY")

# Make API call - traces are automatically sent
response = client.chat.completions.create(
    model="gpt-3.5-turbo",
    messages=[{"role": "user", "content": "Hello"}],
    temperature=0.7,
    max_tokens=150
)

Best Practices

Always include required attributes (vendor, model, messages, path)
Generate unique trace and span IDs for each request
Use accurate timestamps for start and end times
Include usage statistics when available
Format message arrays and tool calls as proper JSON strings
Use the OpenTelemetry user agent to ensure proper trace processing
Include resource attributes with service information
Use proper OpenTelemetry value format (stringValue/intValue) for attributes

Getting Started

Tracing

Prompting

Evaluations & Testing

Supported Integrations

API Reference

Hosting

Contact Us

Chat completion

Sending OpenAI Chat Completion Traces

Prerequisites

Endpoint

Headers

Trace Format

Example cURL Command

Required Attributes

Function Calling Example

Response Format

Success Response

Error Response

Comparison with SDK Usage

Best Practices

​Sending OpenAI Chat Completion Traces

​Prerequisites

​Endpoint

​Headers

​Trace Format

​Example cURL Command

​Required Attributes

​Function Calling Example

​Response Format

​Success Response

​Error Response

​Comparison with SDK Usage

​Best Practices

Sending OpenAI Chat Completion Traces

Prerequisites

Endpoint

Headers

Trace Format

Example cURL Command

Required Attributes

Function Calling Example

Response Format

Success Response

Error Response

Comparison with SDK Usage

Best Practices